Hi,I have a bluetooth module rated max at 3.3v, and an Arduino pro mini ATmega168, at 5v. When I power the bluetooth module through a resistor divider (1.2k +2.2k) I get around 1.68v only to the bluetooth module. Can somebody explain to my why this happens? Does anyone know how to power a 3.3v module from a 5v arduino?

"You gotta fight - for your right - to party!"Don't react - Read."Who is like unto the beast? who is able to make war with him?"It's "bipolar transistor" or "junction transistor" - "BJT" is just stupid.When all else fails, check your wiring!

That Circuit Might work, If regulation wasn't important (It will vary about 300 mV from no load to about 200 mA and it isn't very thermally stable, Diodes are commonly used as temperature sensors in IC's like Processors. After all there's a whole lot of diodes in a Processor. It is also missing a 47uF cap. No Power supply should ever be without some bypassing. The voltage will range from about 750mV @ 0 C to about - 500 550 mV @ 80 C @ 100mA current. Not a lot really considering digital electronics but more than enough to vreate problems with any linear circuitry.

Bob

--> WA7EMS "The solution of every problem is another problem." -Johann Wolfgang von GoetheI do answer technical questions PM'd to me with whatever is in my clipboard

Oh, man.The diodes are sound enough. The OP's just cobbling something together.Does everything have to meet über-stringent design criteria?If someone was working on something so critical that 2 mV per deg_C really mattered then he wouldn't be asking questions here anyway.For that matter, I bet that the BT has on-board decoupling.The diodes, something that everyone needs several of in his indispensable box of stuff, ought to enable the OP to get on with it - a practical means for the present.

"You gotta fight - for your right - to party!"Don't react - Read."Who is like unto the beast? who is able to make war with him?"It's "bipolar transistor" or "junction transistor" - "BJT" is just stupid.When all else fails, check your wiring!

"You gotta fight - for your right - to party!"Don't react - Read."Who is like unto the beast? who is able to make war with him?"It's "bipolar transistor" or "junction transistor" - "BJT" is just stupid.When all else fails, check your wiring!